Interlocking biomedical implant fastener and washer concepts

ABSTRACT

Biomedical implant fastener systems, such as bone screw systems and the like. In some embodiments, a fastener may comprise a first plurality of teeth, and a washer configured to be received on the fastener may comprise a second plurality of teeth configured to be engaged with the first plurality of teeth. The first plurality of teeth may be configured to engage with the second plurality of teeth such that so as to allow for selective rotation between the washer and the fastener in a first rotational direction and so as to prevent rotation between the washer and the fastener in a second rotational direction opposite from the first rotational direction when the fastener is engaged with the washer such that second plurality of teeth is engaged with the first plurality of teeth so as to prevent the fastener from backing out of the washer after engagement.

RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.12/579,667, filed on Oct. 15, 2009 and titled “INTERLOCKING BONE SCREWAND WASHER CONCEPTS,” which claims the benefit of priority of U.S.Provisional Patent Application No. 61/105,545, filed on Oct. 15, 2008and titled “INTERLOCKING BONE SCREW AND WASHER CONCEPTS,” the entirecontents both of which are hereby incorporated by reference herein.

FIELD OF THE INVENTION

The present invention relates generally to a surgically-implantablespinal or other anatomical assembly. More specifically, in someembodiments, the present invention relates to a biomedical implantfastener system, such as a cannulated bone screw system.

BACKGROUND OF THE INVENTION

In various cases, it is desirable to immobilize a facet joint of thespine (e.g. in support of a spinal fusion, etc.) by means other thanconventional pedicle screw systems. A variety of surgically-implantabledevices and assemblies have been developed in order to address suchcases. Typically, these devices and assemblies utilize a singletransfacet bolt or the like that is disposed through a bore drilledthrough the superior and inferior facets of the facet joint. However,not all spinal morphologies support the utilization of such a transfacetbolt, and the utilization of such a transfacet bolt can be clumsydepending upon the application. In such cases, the use of an alternativedevice or assembly is desirable. However, no such alternative devices orassemblies are currently available or in existence.

BRIEF SUMMARY OF THE INVENTION

In an exemplary embodiment of the present invention, a cannulated bonescrew system includes a screw with a threaded portion, a non-threadedportion, and a first plurality of teeth spaced apart from a screw head;and a washer with an interior portion with a second plurality of teethand an opening and an outer portion with a plurality of spikes. Thefirst plurality of teeth are on an inferior convex surface; wherein thesecond plurality of teeth are on a superior concave surface; and whereinthe first plurality of teeth and the second plurality of teeth areoperable to mate to prevent the screw from backing out of the washerwhile allowing the cannulated bone screw system to conform/pivot inorder to accommodate different bone morphologies. The screw head caninclude keyed flanged heads. The cannulated bone screw system canfurther include a screw holder operable to engage the keyed flangedheads. Optionally, the cannulated bone screw system further includes ascrew holder assembly disposed to the screw holder. Alternatively, thecannulated bone screw system further includes a rescue screw assemblydisposed to the screw holder. The plurality of spikes are operable toengage a bone. The screw can be driven into the washer positioned at apilot hole in a bone at an angle. Optionally, the bone includes a firstfacet joint and a second facet joint; wherein the pilot hole is locatedon the first facet joint; wherein the plurality of spikes are engaged tothe first facet joint; and wherein the threaded portion is positionedwithin the second facet joint. The cannulated bone screw system canfurther include a drill guide and washer holder comprising an endclasping mechanism. Optionally, the end clasping mechanism includes aninserter tube that contains the washer.

In another exemplary embodiment of the present invention, a cannulatedbone screw system includes a screw with a threaded portion, anon-threaded portion, and a first plurality of teeth spaced apart from ascrew head; and a washer with an interior portion with a secondplurality of teeth and an opening and an outer portion with a pluralityof spikes; wherein the second plurality of teeth are on a superiorconcave surface; and wherein the first plurality of teeth and the secondplurality of teeth are operable to mate to prevent the screw frombacking out of the washer while allowing the cannulated bone screwsystem to conform/pivot in order to accommodate different bonemorphologies. The cannulated bone screw system can further include meansfor holding the screw, means for positioning the washer, means fordrilling a pilot hole, and means for inserting the screw into the pilothole.

In yet another exemplary embodiment of the present invention, a methodof screwing a cannulated bone screw into a bone includes positioning awasher on the bone; drilling a pilot hole; engaging a cannulated bonescrew; positioning the cannulated bone screw at the pilot hole; screwingthe cannulated bone screw into the pilot hole; engaging the cannulatedbone screw to the washer; and applying rotational force to drive aplurality of spikes on the washer into the bone. The cannulated bonescrew can include a first plurality of teeth spaced apart from a screwhead; and the washer can include an interior portion with a secondplurality of teeth and an opening and an outer portion with theplurality of spikes. The first plurality of teeth are on an inferiorconvex surface; wherein the second plurality of teeth are on a superiorconcave surface; and wherein the first plurality of teeth and the secondplurality of teeth are operable to mate to prevent the screw frombacking out of the washer while allowing the cannulated bone screwsystem to conform/pivot in order to accommodate different bonemorphologies.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention is illustrated and described herein with referenceto the various drawings, m which like reference numbers denote likesystem components/method steps, as appropriate, and in which:

FIG. 1 illustrates different views of a cannulated bone screw accordingto an exemplary embodiment of the present invention;

FIG. 2 illustrates a close up view of the radial interlocking convextoothed surface and the screw head of the cannulated bone screw of FIG.1 according to an exemplary embodiment of the present invention;

FIG. 3 illustrates different views of a washer for mating with thecannulated bone screw of FIG. 1 according to an exemplary embodiment ofthe present invention;

FIG. 4 illustrates the cannulated bone screw of FIG. 1 engaged with thewasher of FIG. 3 according to an exemplary embodiment of the presentinvention;

FIG. 5 illustrates a screw holder for engaging the screw head of thecannulated bone screw of FIG. 1 according to an exemplary embodiment ofthe present invention;

FIG. 6 illustrates a bone screw and screw holder assembly according toan exemplary embodiment of the present invention;

FIG. 7 illustrates a rescue screw system assembly for removing thecannulated bone screw of FIG. 1 according to an exemplary embodiment ofthe present invention;

FIG. 8 illustrates a cannulated bone screw and a washer according toanother exemplary embodiment of the present invention;

FIG. 9 illustrates the cannulated bone screw engaged with the washeraccording to an exemplary embodiment of the present invention;

FIG. 10 illustrates a drill guide and washer holder according to anexemplary embodiment of the present invention;

FIG. 11 illustrates different views of a cannulated drill according toan exemplary embodiment of the present invention;

FIG. 12 illustrates different views of a screw holder assembly 1200 anda screw holder for the cannulated bone screw of FIG. 8 according to anexemplary embodiment of the present invention;

FIG. 13 illustrates a screw driver with a hexalobular design accordingto an exemplary embodiment of the present invention;

FIG. 14 illustrates a rescue screw system according to an exemplaryembodiment of the present invention; and

FIG. 15 illustrates different views of the rescue screw system of FIG.14 according to an exemplary embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

Referring to FIG. 1, different views are illustrated of a cannulatedbone screw 100 according to an exemplary embodiment of the presentinvention. The cannulated bone screw 100 includes a threaded end portion102, a non-threaded portion 104, and a radial interlocking convextoothed surface 106 disposed near a screw head 108. The threaded endportion 102 is operable to screw into a bone, such as a facet joint orthe like. The cannulated bone screw 100 can be utilized to stabilizefacet joints through an angular insertion of the cannulated bone screw100 into a first facet and screwing the cannulated bone screw 100 into asecond facet, the associated pedicle, or any other bony structure. Oncefully engaged between the facets, the associated pedicle, or any otherbony structure, the threaded portion 102 is embedded in the secondfacet, the associated pedicle, or any other bony structure, and thenon-threaded portion 104 is in the first facet. Additionally, a washer(FIG. 3) is operable to engage the screw head 108 and an outer surfaceof the first facet. It should be noted that any suitable guide holes orbores can be utilized in achieving the placement/securement of thecannulated bone screw 100.

Referring to FIG. 2, a close up view illustrates the radial interlockingconvex toothed surface 106 and the screw head 108 of the cannulated bonescrew 100 according to an exemplary embodiment of the present invention.The screw head 108 includes a unique slotted head flange that holds anddrives the cannulated bone screw 100 into a facet joint or the like. Theunique head flange design holds bone screw 100 securely as well aspermitting initial thread engagement into a pilot hole. The radialinterlocking convex toothed surface 106 includes a radial toothedpattern on an inferior convex surface that is configured to mate with asuperior concave surface of a washer, as depicted in FIG. 3. Anysuitable radial toothed pattern and mating superior concave surface canbe utilized, as long as relative rotational between the two structuresis selectively prevented upon engagement.

Referring to FIG. 3, different views are illustrated of a washer 300 formating with the cannulated bone screw 100 according to an exemplaryembodiment of the present invention. The washer 300 includes aconcentric shape dimensioned responsive to the cannulated bone screw100. The washer 300 includes an opening 302 for receiving the threadedend portion 102 and the non-threaded portion 104 of the cannulated bonescrew 100. An interior of the washer 300 includes an interlocking radialtoothed pattern on a superior concave surface 304. The superior concavesurface 304 is configured to mate with the inferior convex surface onthe radial interlocking convex toothed surface 106. The interlockingteeth between the washer 300 and the screw head 108 advantageouslyprevent rotational loosening of the cannulated bone screw 100. A bottomportion 310 of the washer 300 includes a plurality of spikes 312. Theplurality of spikes 312 are configured to engage a bone when thecannulated bone screw 100 and the washer 300 are screwed into the bone.It should be noted that, throughout, spikes can be replaced with anysuitable frictional surface for preventing movement and/or rotation.

Referring to FIG. 4, the cannulated bone screw 100 is illustratedengaged with the washer 300 according to an exemplary embodiment of thepresent invention. The opening 302 of the washer 300 is slid over thethreaded portion 102 to the non-threaded portion 104. As the threadedportion 102 is screwed into a bone, the spikes 312 on the washer 300engage the bone, and the washer 300 engages the radial interlockingconvex toothed surface 106 on the cannulated bone screw 100. In thelocked position, the interlocking concave/convex surfaces on the toothedsurface 106 and the washer 300 prevent the screw from backing out whileallowing the cannulated bone screw 100 to conform/pivot in order toaccommodate different bone morphologies.

Referring to FIG. 5, a screw holder 500 is illustrated for engaging thescrew head 108 according to an exemplary embodiment of the presentinvention. FIG. 5 illustrates the screw holder 500 disengaged from andengaged to the screw head 108. The screw holder 500 is configured tosnap over keyed head flanges 502 in the screw head 108. The screw holder500 includes a first arc member 510 and a second arc member 512, eachconfigured to engage one of the keyed head flanges 502 in the screw head108. The arc members 510, 512 each include a notch 514 which snaps onthe keyed head flanges 502, and a top of the arc members 510, 512substantially mates with a top side 520 of the toothed surface 106. Thescrew holder 500 further includes a first arc portion 522 and a secondarc portion 524 offset from the arc members 510, 512. The arc portions522, 524 are operable to engage a top 526 of the screw head 108 when thearc members 510, 512 are engaged to the keyed head flanges 502.Collectively, the arc members 510, 512 and the arc portions 522, 524define notches 526 which are operable to engage the keyed head flanges502. In the engaged position, the screw holder 500 is operable totranslate a rotational force to the cannulated bone screw 100 to enableengagement of the washer 300 and a bone. The screw holder 500 alsofurther includes a first support member 530 and a second support member532. Each of the support members 530, 532 are disposed to the arcmembers 510, 512, and the arc portions 522, 524 extend from the supportmembers 530, 532.

Referring to FIG. 6, a bone screw and screw holder assembly 600 isillustrated according to an exemplary embodiment of the presentinvention. The bone screw and screw holder assembly 600 is operable toengage the screw holder 500 and the cannulated bone screw 100 forinsertion into a bone. The support members 530, 532 of the screw holder500 are each disposed to a cylinder section 540. The cylinder section540 engages a coupling mechanism 602 which enables the bone screw andscrew holder assembly 600 to engage the screw holder 500. Note, thecoupling mechanism 602 can be disposed on the screw holder 500, on thebone screw and screw holder assembly 600, or separate from both. Thecoupling mechanism 602 is configured to provide engagement between thescrew holder 500 and the bone screw and screw holder assembly 600. Acylinder portion 604 of the bone screw and screw holder assembly 600extends from the coupling mechanism 602 to a handle portion 606. Thehandle portion 606 can include a T-shaped handle 608 and a grip portion610. In operation, a surgeon utilizes the bone screw and screw holderassembly 600 to engage the screw holder 500 and the cannulated bonescrew 100. The handle portion 606 enables the surgeon to insert thethreaded portion 102 and the non-threaded portion 104 into a bone.

Referring to FIG. 7, a rescue screw system assembly 700 is illustratedfor removing the cannulated bone screw 100 according to an exemplaryembodiment of the present invention. The rescue screw system assembly700 engages the cannulated bone screw 100 in a similar fashion as thescrew holder 500 as described in FIG. 5. The rescue screw systemassembly 700 includes a cylinder member 702 disposed to an engagementmechanism 704 at one end. The engagement mechanism 704 is configured toengage the cannulated bone screw 100. A grip portion 706 is disposed atanother end of the cylinder member 702. A handle portion 708 is disposedto the grip portion 706. Collectively, a surgeon can utilize the gripportion 706 and the handle portion 708 to maneuver the rescue screwsystem assembly 700 to engage the cannulated bone screw 100, and tosubsequently remove the cannulated bone screw 100 through rotationalforce imposed through the grip portion 706 and the handle portion 708.

Referring to FIG. 8, a cannulated bone screw 800 and a washer 802 areillustrated according to an exemplary embodiment of the presentinvention. The cannulated bone screw 100 includes a threaded end portion804, a non-threaded portion 806, and a radial interlocking convextoothed surface 808 disposed near a screw head 810. The screw head 810includes keyed head flanges 812 for engaging a screw holder, drill, orthe like. The threaded end portion 804 is operable to screw into a bone,such as a facet joint or the like. The cannulated bone screw 800 can beutilized to stabilize facet joints through an angular insertion of thecannulated bone screw 800 into a first facet and screwing the cannulatedbone screw 800 into a second facet, the associated pedicle, or any otherbony structure. Once fully engaged between the facets, pedicle, or otherbony structure, the threaded portion 804 is embedded in the secondfacet, the associated pedicle, or any other bony structure, and thenon-threaded portion 806 is in the first facet. Additionally, the washer802 is operable to engage the screw head 108 and an outer surface of thefirst facet through a plurality of spikes 820 located on a bottom sideof the washer 802. An interior of the washer 802 includes aninterlocking radial toothed pattern 830 on a superior concave surface.The washer 802 further includes an opening 832 dimensioned to receivethe cannulated bone screw 800. The interlocking radial toothed pattern830 is operable to engage the radial interlocking convex toothed surface808 to prevent rotational loosening of the cannulated bone screw 800.

Referring to FIG. 9, the cannulated bone screw 800 is illustratedengaged with the washer 802 according to an exemplary embodiment of thepresent invention. The opening 832 of the washer 800 is slid over thethreaded portion 804 to the non-threaded portion 806. As the threadedportion 804 is screwed into a bone, the spikes 820 on the washer 802engage the bone, and the washer 802 engages the radial interlockingconvex toothed surface 808 on the cannulated bone screw 800. In thelocked position, the interlocking concave/convex surfaces on the toothedsurface 808 and the washer 802 prevent the screw from backing out whileallowing the cannulated bone screw 800 to conform/pivot in order toaccommodate different bone morphologies.

Referring to FIG. 10, a drill guide and washer holder 1000 isillustrated according to an exemplary embodiment of the presentinvention. The drill guide and washer holder 1000 is operable to placethe washer 802 on a surface, i.e. bone, and to guide a drill with thecannulated bone screw 800 through the washer 802 and the bone. The drillguide and washer holder 1000 includes a handle portion 1002, a cylindermember 1004 disposed to the handle portion 1002, and an end claspingmechanism 1006 disposed to an end of the cylinder member 1004. The endclasping mechanism 1006 is configured to grasp and place the washer 802.For example, the end clasping mechanism 1006 can include an insertertube that contains the washer 802. The handle portion 1002 includes adrill opening 1010 operable to receive a drill. The opening 1010 extendsthrough the handle portion 1002, the cylinder member 1004, and the endclasping mechanism 1006 to enable the drill to engage the washer 802 andextend out of the end clasping mechanism 1006 to a bony structure or thelike.

Referring to FIG. 11, different views are illustrated of a cannulateddrill 1100 according to an exemplary embodiment of the presentinvention. The cannulated drill 1100 can be utilized with the drillguide and washer holder 1000 to drill a pilot hole in a bone to receivethe cannulated bone screw 800. The cannulated drill 1100 includes adrill bit 1102 which in an exemplary embodiment may be 4 mm. The drillbit 1102 can be removable from the cannulated drill 1100 through acoupling mechanism 1104 disposed to an end of the cannulated drill 1100.The coupling mechanism 1104 is disposed to a cylinder member 1106 whichextends to a drill connection point 1108. The drill connection point1108 includes a connector 1110 for interfacing to a drill element. Theconnector 1110 translates a rotational force from the drill elementthrough the cylinder member 1106 to enable the drill bit 1102 to rotatefor drilling the pilot hole in a bone. For example, the cannulated drill1100 can be utilized in the drill opening 1010 of the drill guide andwasher holder 1000.

Referring to FIG. 12, different views are illustrated of a screw holderassembly 1200 and a screw holder 1202 for the cannulated bone screw 800according to an exemplary embodiment of the present invention. The screwholder 1202 is operable to engage the screw head 810 through the keyedhead flanges 812 on the cannulated bone screw 800. For example, thescrew holder 1202 can utilize similar mechanisms as described herein inFIG. 5. The screw holder 1202 is configured to snap over the keyed headflanges 812 in the screw head 810. The screw holder 1202 includes afirst arc member 1204 and a second arc member 1206, each configured toengage one of the keyed head flanges 812 in the screw head 810. The arcmembers 1204, 1206 each include a notch (not shown) which snaps on thekeyed head flanges 812, and a top of the arc members 1204, 1206substantially mates with a top side of the toothed surface 808. Thescrew holder 1202 further includes a first arc portion 1208 and a secondarc portion 1210 offset from the arc members 1204, 1206. The arcportions 1208, 1210 are operable to engage a top 1212 of the screw head810 when the arc members 1204, 1206 are engaged to the keyed headflanges 812. Collectively, the arc members 1204, 1206 and the arcportions 1208, 1210 define notches which are operable to engage thekeyed head flanges 812. In the engaged position, the screw holder 1202is operable to translate a rotational force to the cannulated bone screw800 to enable engagement of the washer 802 and a bone, such as through apilot hole. The screw holder 1202 also further includes a first supportmember 1220 and a second support member 1222. Each of the supportmembers 1220, 1222 are disposed to the arc members 1204, 1206, and thearc portions 1208, 1210 extend from the support members 1220, 1222. Thesupport members 1220, 1222 are disposed to a cylinder member 1230.

The screw holder assembly 1200 is operable to engage the screw holder1202 through a coupling mechanism 1240. The coupling mechanism 1240 canbe disposed to the screw holder 1202, to a cylinder member 1242, or toneither. The cylinder member 1242 extends to a handle 1244. A surgeoncan utilize the handle 1244 while griping onto the cylinder member 1242to maneuver the screw holder assembly 1200 to engage the cannulated bonescrew 800, to position the cannulated bone screw 800 into a washer 802and pilot hole, and to screw the cannulated bone screw 800 into thebone.

Referring to FIG. 13, a screw driver assembly 1300 is illustrated with ahexalobular design 1304 for a screw holder 1302 according to anexemplary embodiment of the present invention. The screw holder 1302 isoperable to engage the screw head 810 through the keyed head flanges 812and through a hexalobular design 1304 on the cannulated bone screw 800.The screw driver assembly 1300 is similar to the screw holder assembly1200 with the addition of the hexalobular design 1304. The screw driverassembly 1300 includes a cylinder member 1310 and a handle 1312. Thecylinder member 1310 includes the screw holder 1302 at one end and thehandle 1312 at the other end.

Referring to FIG. 14, a rescue screw system 1400 is illustratedaccording to an exemplary embodiment of the present invention. Therescue screw system 1400 is operable to remove an inserted cannulatedbone screw 800. The rescue screw system 1400 includes one of the screwholders 1202, 1302, a cylinder member 1402 disposed to the screw holder1202, 1302 at one end and to a grip portion 1404 at another end, and ahandle portion 1406 disposed to the grip portion 1404. A surgeon canutilize the rescue screw system 1400 to engage the cannulated bone screw800 and remove the cannulated bone screw 800 through rotational forceapplied through the grip portion 1404 and the handle portion 1406.

Referring to FIG. 15, different views are illustrated of the rescuescrew system 1400 of FIG. 14 according to an exemplary embodiment of thepresent invention. FIG. 15 illustrates a close-up view of the handleportion 1406 and the grip portion 1404, and a close-up view of thecannulated bone screw 80 engaged to the screw holder 1202, 1302.

Although the present invention has been illustrated and described hereinwith reference to preferred embodiments and specific examples thereof,it will be readily apparent to those of ordinary skill in the art thatother embodiments and examples may perform similar functions and/orachieve like results. All such equivalent embodiments and examples arewithin the spirit and scope of the present invention, are contemplatedthereby, and are intended to be covered by the following claims.

The invention claimed is:
 1. A biomedical implant fastener system,comprising: a fastener comprising a first plurality of teeth; and awasher comprising a second plurality of teeth configured to be engagedwith the first plurality of teeth, wherein the first plurality of teethand the second plurality of teeth are configured such that, when thefirst plurality of teeth is engaged with the second plurality of teeth,the fastener is allowed to pivot with respect to the washer while stillpreventing the fastener from backing out of the washer.
 2. Thebiomedical implant fastener system of claim 1, wherein the fastenercomprises a bone screw.
 3. The biomedical implant fastener system ofclaim 2, wherein the bone screw comprises a cannulated bone screw. 4.The biomedical implant fastener system of claim 2, wherein the washerfurther comprises a frictional surface positioned along a lower surfaceof the washer that is configured for engaging a bony structure below thewasher.
 5. The biomedical implant fastener system of claim 4, whereinthe frictional surface comprises a plurality of spikes.
 6. Thebiomedical implant fastener system of claim 1, wherein the biomedicalimplant fastener system is configured to be used with at least one of athoracolumbar fixation plate, an anterior lumbar fixation plate, astand-alone intervertebral spacer, a bone fracture fixation plate, and aspinal fixation system comprising a pedicle screw.
 7. The biomedicalimplant fastener system of claim 1, wherein the fastener furthercomprises a fastener head, and wherein the fastener head is spaced apartfrom the first plurality of teeth.
 8. The biomedical implant fastenersystem of claim 1, wherein the first plurality of teeth is rigidlyaffixed to an inferior convex surface of the fastener; and wherein thesecond plurality of teeth is positioned on a superior concave surface ofthe washer.
 9. The biomedical implant fastener system of claim 1,wherein the first plurality of teeth comprises a radial toothed pattern.10. The biomedical implant fastener system of claim 1, wherein thefastener comprises a bone screw, and wherein the bone screw isconfigured to be driven into the washer positioned at a pilot hole in abone at an angle with respect to an opening in the washer.
 11. Abiomedical implant fastener system, comprising: a fastener comprising afirst plurality of teeth; and a washer comprising a second plurality ofteeth configured to be engaged with the first plurality of teeth,wherein the first plurality of teeth is configured to engage with thesecond plurality of teeth such that so as to allow for selectiverotation between the washer and the fastener in a first rotationaldirection and so as to prevent rotation between the washer and thefastener in a second rotational direction opposite from the firstrotational direction when the fastener is engaged with the washer suchthat the second plurality of teeth is engaged with the first pluralityof teeth.
 12. The biomedical implant fastener system of claim 11,wherein the first plurality of teeth and the second plurality of teethare configured to engage with one another such that, when the firstplurality of teeth is engaged with the second plurality of teeth, thewasher is allowed to at least one of conform and pivot with respect tothe fastener.
 13. The biomedical implant fastener system of claim 11,wherein the fastener comprises a bone screw, and wherein the bone screwis configured to at least one of conform and pivot with respect to thewasher when the first plurality of teeth is engaged with the secondplurality of teeth in order to accommodate different bone morphologies.14. The biomedical implant fastener system of claim 11, wherein thesystem is configured such that the fastener can be placed at variableconical angles with respect to the washer when the first plurality ofteeth is engaged with the second plurality of teeth.
 15. A bone screwsystem, comprising: a bone screw comprising a first plurality of teethand a threaded portion configured to engage a bony structure, whereinthe first plurality of teeth is rigidly affixed to the bone screw, andwherein the threaded portion is spaced apart from the first plurality ofteeth; and a washer comprising an interior portion comprising a secondplurality of teeth, wherein the first plurality of teeth and the secondplurality of teeth are configured to mate to prevent the bone screw frombacking out of the washer, and such that, when the first plurality ofteeth is engaged with the second plurality of teeth, allowing at leastone of the bone screw and the washer to at least one of conform andpivot in order to accommodate different bone morphologies.
 16. The bonescrew system of claim 15, wherein the bone screw further comprises abone screw head, wherein the bone screw head is spaced apart from thefirst plurality of teeth, and wherein the first plurality of teeth isoriented away from the bone screw head.
 17. The bone screw system ofclaim 15, wherein the washer comprises a frictional surface configuredfor engaging the bony structure.
 18. The bone screw system of claim 15,wherein the first plurality of teeth comprise uni-directional teeth, andwherein the second plurality of teeth comprise uni-directional teeth.19. The bone screw system of claim 15, wherein the first plurality ofteeth and the second plurality of teeth are configured to mate to allowthe bone screw to advance and rotate in a first direction, and whereinthe first plurality of teeth and the second plurality of teeth arefurther configured prevent the bone screw from rotating in a seconddirection opposite from the first direction once the first plurality ofteeth has been engaged with the second plurality of teeth.
 20. The bonescrew system of claim 15, wherein the bone screw further comprises anon-threaded section.
 21. The bone screw system of claim 20, wherein thenon-threaded section is positioned between the threaded section and thefirst plurality of teeth.
 22. The bone screw system of claim 21, whereinthe bone screw is configured such that the non-threaded section isconfigured to engage a first bony portion and such that the threadedsection is configured to engage a second bony portion.